Suppose a train-based observer in Question 37 measures the length of the train to be 400...

Suppose a train-based observer in Question 37 measures the length of the train to be 400 meters. He then places exploding paint cans on the front and back of the train and detonates them simultaneously. An observer on the ground then measures the distance between the paint splatters left on the tracks. Will her measurement be less than, equal to, or greater than 400 meters? Why?